


Transfiguration With Regulus Black

by Tachi_Sakon



Category: Harry Potter - J. K. Rowling
Genre: Animagus, Brothers, Cats, Established Relationship, F/M, Fights, Fluff, Gen, Height Differences, Magic, Marauders, Marauders Era (Harry Potter), Multi, Other Additional Tags to Be Added, Other Ships Not Mentioned in Tags, Platonic Relationships, Pre-Canon, Protective Older Brothers, Regulus Black-centric, Regulus loves cats, Regulus reads minds, Tickle Fights, Transfiguration (Harry Potter), Transfiguration Troubles, misuse of magic, short Regulus
Language: English
Status: In-Progress
Published: 2020-10-27
Updated: 2020-10-27
Packaged: 2021-03-08 21:33:41
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,316
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27223543
Author URL: https://archiveofourown.org/users/Tachi_Sakon/pseuds/Tachi_Sakon
Summary: "Fucking Merlin's pants," Sirius groaned, "why would you do that Reg?"Regulus glanced up at his brother, large doe eyes wide as he fluttered his lashes. "Merlin's pants?" He echoed. "Really Sirius, all the metaphors in the world and you go with Merlin's pants?""Don't switch the subject!" Sirius growled.Regulus bit at the inside of his cheek and looked down at the feline in his lap. "I just.." he murmured."'You just', what?!""I just wanted a cat."
Relationships: Arthur Weasley/Molly Weasley, James Potter/Lily Evans Potter, Lucius Malfoy/Narcissa Black Malfoy, Other Relationship Tags to Be Added, Regulus Black & Bellatrix Black Lestrange, Regulus Black & Black Family, Regulus Black & James Potter, Regulus Black & Kreacher, Regulus Black & Lucius Malfoy, Regulus Black & Peter Pettigrew, Regulus Black & Remus Lupin, Regulus Black & Severus Snape, Regulus Black & Sirius Black, Sirius Black & Remus Lupin & Peter Pettigrew & James Potter, Sirius Black/Remus Lupin
Comments: 8
Kudos: 78





	Transfiguration With Regulus Black

**Author's Note:**

> I forgot how to spell Regulus’ middle name, I’m sorry ;-: 
> 
> And it is my personal headcanon that Regulus is a short and adorable, cat loving git <3 I love him

* * *

_A cat._

_This was all because Regulus Archius Black had wanted a cat._

When Sirius Orion Black stormed into the Slytherin dorms that night, he was not expecting to see his little brother perched on his bed with a huge smile on his face as he stroked a large black cat.

"Regulus Archius _fucking_ Black!" 

The younger Black jumped up on the bed with a high squeal, the cat hissing with its fur on end, before settling back down into the mattress with a sigh. "Oh, it's only Sirius." He breathed in relief as he gestured to the cat with his hands. "Come back here,"    
  


He looked up at his brother with a frown, "You scared him."

_More like I scared you, but that isn't the point, you dimwit!_

Regulus rolled his eyes. "I know Occlumens, remember?"

"That doesn't matter,"

"Whatever you say."

"And besides, what do you mean," Sirius ground out through gritted teeth and imitating his brother's higher voice, "' _it's only Sirius'?_!" 

"Exactly what it sounds like." Regulus replied easily, quirking an eyebrow at his older brother. "Or did you loose all senses of hearing too?"

It took all of Sirius' self restraint to keep himself from launching at his younger brother and strangling him. Settling on clenching his fists at his sides, he stomped over to the bed and halted loudly in front of Regulus. "Don't be such a fucking prick, Reg." He hissed before reaching out and jabbing a finger at the cat now curled up in Regulus' lap. "I knew that you were always a bit off your rocker, but _this_ —" he groaned and slapped his forehead, "is just what normal people would call when the hat falls off!"

"Oh?" Regulus hummed, ignoring his older brother and continuing to pet the cat with the same smile he wore all the time still sewn on his childish face. "Since when were you _normal_ , Sirius?"

"Touché, Reg, touché."

The two brothers fell into silence, the only sounds in the room being the soft purring and rumbling sounding from the cat in Regulus' lap.

Sirius found himself having a glare-off with the black cat and Regulus could see sparks practically flying.

"Will you two stop being so childish?" He sighed, pausing his stroking and earning himself a hiss from the cat.

Sirius turned his glare from the cat to his brother. "I will," he huffed, "when you tell me why you thought it was a _good_ idea to turn your dorm-mate into a fucking cat!"

Regulus pushed his lower lip into a pout and frowned. The cat hissed and nudged it's head into his lap, pawing at his hand. The younger black heaved a sigh and returned to petting the cat in slow and gentle motions until he settled down and lay completely sprawled out over his legs and thighs, nuzzling his laps.

Sirius' temper raised higher and higher by the minute as his brother ignored him by occupying himself with the cat.

"Fucking Merlin's pants," he groaned, "why would you do that Reg?"

Regulus glanced up at his brother, large doe eyes wide as he fluttered his lashes. "Merlin's pants?" He repeated with a small laugh. "Really Sirius, all the metaphors in the wizarding world and you go with _Merlin's pants_?"

"Don't switch the subject!" Sirius growled. "Answer me, god dammit!"

Regulus bit at the inside of his cheek and looked down at the feline in his lap. "I just.." he murmured.

"'You just', what?!" 

Sirius glared at Regulus, who was averting his gaze and biting the insides of his cheeks, running his hands along the cat's backside. Crossing his arms over his chest, his brows furrowed even more. "Well?" Sirius prompted angrily, tapping his arms with his fingers. "I'm waiting for you to fucking answer me."

Regulus sucked on his lower lip before mumbling, ".. just wanted.."

Sirius leaned forward, " _Huh_?!"

Regulus sighed and repeated, his voice soft with embarrassment and still filled out cheeks flushing, "I just wanted a cat."   
  


"You should know by now that transfiguring your classmate into an animal isn't the way to get what you want!" Sirius yelled at his brother, waving his arms wildly. "What are you? _Five_?!"

Regulus poured at Sirius. "But it worked," he huffed gathering the cat into his arms and holding him close to his chest. "I have a cat now!"

"Who did you even talk into turning into a cat?!"

"Lucius,"

"Turn him back!" Sirius shouted. "And get him off you, that's fucking perverted! Gross," he racked his brain for things to associate with the cat in Regulus' arms, "awful, _illegal_!"

"You're the perverted one for thinking like that." Regulus hissed. "And this isn't _illegal_ you stupid git, he's just enjoying being a cat." The childish fifth year looked back down at the cat and began to scratch under his chin, smiling as the cat purred happily, “aren't you Lucius? Who's a good kitty, who's a good kitty?"

Sirius mimed gagging and stuck his tongue out. "That's disgusting," he scoffed with a grimace.

Regulus turned his unimpressed glare to his brother, tilting his head. "You're disgusting, Sirius."

"No you are!" Sirius retorted, glaring back at Regulus. "Look at you, all gushy.. and with him!”

"He makes a cute cat!"

"Like hell he does!"

"Look at him!" Regulus whined holding up his transfigured classmate to Sirius. "Isn't he so cute?"

"No!"

"Stingy,"

"I'm not stingy, I'm normal!"

Regulus gasped in mock shock. " _You_?" He asked incredulously, pointing at his brother. " _Normal_?"

"Shut your snake hole," Sirius growled, "before I become _abnormal_."

Regulus gave a soft snort as the cat nuzzled up and against his cheeks, wrapping his arms around the cat in a hug. "Again, since when have you ever been normal in the _first_ place?"

Sirius pinches his temples. Sometimes, he wanted nothing more than to strangle his little brother. "Regulus take this seriously, please."

"But I'm not Sirius,"

" _Regulus_!" 

"Alright, alright.."

Sirius watched Regulus gently place the cat down on the bed before standing up and hopping off the mattress. The younger Black blew his long bangs out of his face and shook his head, reminding Sirius of a cat himself and making him wonder briefly if his animagus happened to be a cat. 

"Turn him back, Reg." Sirius sighed. "You can't use your dorm-mate, even if he is a selfish git," he sent a glare the cat's way, smirking as it hissed at him, "as a pet."

Regulus was now standing in front of Sirius, nearly as tall as him if not for him inheriting his father's height and short legs, arms crossed over his chest, tapping his wand on his left arm and lips pursed. "You lost the right to tell me what to do the moment you left home." He hissed, quickly stepping forwards and jabbing the tip of his wand into his older brother's chest, making him stumble back. "So don't act like an older brother now." 

"Don't be stupid," Sirius snapped back, rubbing at his chest with his hand, leveling gazes with Regulus. "I'm your older brother, and I'm telling you to turn _that_ ," he pointed at the cat curled around Regulus' feet, "back into a human!"

"Don't call my cat a _that_ , you pompous Gryffindor!"

"Then don't be such a prick, you slimy Slytherin!"

Regulus visibly recoiled before gritting his teeth. "It's none of your business _what_ I do," he snapped, voice rising with every syllable until he was shouting, "and _who_ I do things with!"

"Yes it is!" Sirius yelled back. "As your brother, I have every right to know!"

"No it isn't!" Regulus shrieked. "No you don't!"

Sirius clenched his hands into fists, breathing heavily. "Why are you so hung up on having a stupid cat to the point where you turned to _Lucius fucking Malfoy_?!"

"Because _that_ ," Regulus breathes angrily, "is a better companion than _you_ ever were and ever will be."


End file.
